fĂĽr alle Nerds: die Golf 2/Golf 3 syncro Hinterachse im Detail
What's the difference between the syncro and the FWD rear axle?
The fundamental difference is obvious: as an all-wheel-drive vehicle, the Syncro requires space at the rear axle for a differential and two drive shafts. Therefore, it's clear that it needs a bigger installation space compared to the rear axle of front-wheel-drive models.
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However, in terms of axis kinematics, the difference is much more significant than you might expect.
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While the front-wheel-drive versions have a so-called torsion beam axle, where the left and right wheels are rigidly connected, Volkswagen equipped the all-wheel-drive versions of the Golf 2 and Golf 3 with independent rear suspension. Yes, independent rear suspension!
Why is it so interesting in terms of driving performance?
It's not that a torsion beam axle is a bad technical solution. It's a good compromise between cost and handling (or rather, driving stability) for mass-produced cars. But from a technical point of view, independent suspension is simply superior:
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WEIGHT: usually independent suspension is lighter (a torsion beam axle needs to withstand torsional forces)
ALIGNMENT: each wheel can be adjusted individually for camber and toe (provided that adjustment options are available - but these actually need to be retrofitted on the syncro axles)
KINEMATICS: the wheel follows a defined, three-dimensional curve, instead of just making a two-dimensional movement (leaving aside the topic of elasto-kinematics in this consideration)
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The project: 3d scanning and reverse engineering the geometry
To better understand the movement of the wheel with the syncro axle, a motion simulation in CAD is practically essential. After all, probably only Volkswagen knows exactly what they designed back then. So we got started:
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step 1 = scanning the parts: we 3d scanned both the Syncro axle body and the two axle journals (from a vehicle with disc brakes) and then combined them in CAD.
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step 2 = reverse engineering in CAD: determining the axes of rotation on axle body and axle journals, including checking for symmetry left to right (always necessary when used parts are used as a basis for a scan) â €
step 3 = motion simulation: incremental rotation around the axis of rotation, tabulation of the values ​​for toe and camber, calculation of the relative toe change over the suspension travel (total stroke from fully extended to fully compressed) ⠀
THE RESULT: a clear illustration of how the single toe behaves during compression and rebound travel. Shown in the following graphic or available as a downloadable PDF document (DE+EN)
You're probably wondering now: what's the point of all this effort?
The toe-in curve of the rear axle significantly determines the vehicle's handling characteristics when cornering. However, while the axle alignment data specified by the vehicle manufacturer offers the best compromise between tire wear and driving dynamics for a standard road vehicle, it is unsuitable for a modified, performance-optimized vehicle.
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Our diagram of the syncro axle toe curve helps you depending on the following factors
finding the static toe setting required to achieve the desired self-steering behavior in dynamic conditions.
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You don't have a syncro at all? Then pay attention!
We are currently working on a conversion kit from torsion beam axle to independent rear suspension, suitable for all front-wheel drive Golf Mk2 and Golf Mk3 models! No more compromises in driving dynamics – out with the torsion beam axle and in with performance. And it's plug & play, without any stressful modifications:
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NO cutting of the body: no need to install the raised trunk floor from the Syncro
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carry over the original fuel tank: it is not necessary to convert to the Syncro tank â €
retaining the FWD exhaust: the exhaust system of the front-wheel drive model can be kept without any modification â €
keep your shock absorbers: the mounting points of the rear struts are in the exact same place compared to the torsion beam axle â €
including camber and toe adjustment: while it needs to be retrofitted on syncro models, our design already features eccentric adjusters to incorporate toe and camber adjustment
